How tos....JTree

Question

To all Java developers out there:
Hi! I would just like to ask for help regarding the implementation of JTrees.
I am trying to make a JTree with an unknown number of directories or files. I have an Application folder. This folder may contain files, subfolders, subfolders with files, subfolders with subfolders with files...etc...The contents of this folder is unkown, that is why I wanted the JTree to be dynamic. Dynamic in the sense that whenever a new file or a new folder or a new subfolder is added, it can automatically be reflected on the JTree which I am trying to make.
Can someone please advise?? Thanks a lot. I appreciate it...

Answer 1

Hi Dev
At first glance, what I think you need is some code
to recursively go through the contents of a folder.
You can feed this information to build a 'tree' of
nodes which you can then pass onto your JTree. I tried to do that but I had a problem with directories. Since the Root folder can contain more than one subfolder, i am not able to get the correct "path name". I am only able to get the subdirectories of one folder.
Root
|_ Folder A
|_ File A
|_Folder B
|_ File B
|_Folder C
I can only get the contents of Folder A but i cannot reach Folder B and Folder C anymore...Maybe there is something wrong with my code...
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
import java.io.*;
import java.util.*;
import java.util.logging.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
import javax.swing.tree.*;
import java.lang.*;
public class ApplicationTree extends JFrame // implements TreeModelListener
     JTree ApplicationTree;
     String fileName = null;
     File fApp;
     public ApplicationTree()
          boolean bValid = checkFile("Library/components/applications");
          if(bValid)
               fApp = new File("Library/components/applications/");          
               DefaultMutableTreeNode dmtnRoot = new DefaultMutableTreeNode("Applications");
               String[] sApp = fApp.list();
          StringBuffer sbApp = new StringBuffer("Library/components/applications/");
          createNodes(dmtnRoot, sApp, sbApp);
               ApplicationTree = new JTree(dmtnRoot, true);
          ApplicationTree.setDragEnabled(true);
          this.getContentPane().add(ApplicationTree);
          this.setSize(300, 200);
          this.setVisible(true);
     public void createNodes(DefaultMutableTreeNode admtnApp, String[] asApp, StringBuffer asbApp)
          for (int nCount = 0; nCount < asApp.length; nCount ++)
               Vector vApp = new Vector();
          vApp.addElement(asApp[nCount]);
               if(fApp.isDirectory())
                    File fAppCont = new File ("Library/components/applications/"+asApp[nCount]);
                    DefaultMutableTreeNode dmtnAppCont = new DefaultMutableTreeNode(asApp[nCount]);
                    if(fAppCont.isDirectory())
                         String[] sAppCont = fAppCont.list();
                         asbApp.append(asApp[nCount]);
                         int iRemove = asbApp.indexOf(asApp[nCount]);
                         System.out.println(iRemove);
                         asbApp.substring(0,iRemove-1);
                         System.out.println(asbApp);
                         createNodes(dmtnAppCont, sAppCont, asbApp);
                         //System.out.println("sApp: "+fApp.list()+ "sbApp: "+asbApp);
                    else if(fAppCont.isFile())
                         DefaultMutableTreeNode dmtnAppContent1 = new DefaultMutableTreeNode(fAppCont.getName());
                         dmtnAppCont.add(dmtnAppContent1);
                    admtnApp.add(dmtnAppCont);
               else if(fApp.isFile())
                    DefaultMutableTreeNode dmtnAppContent2 = new DefaultMutableTreeNode(fApp.getName());
                    admtnApp.add(dmtnAppContent2);
     public boolean checkFile(String path)
          boolean exists = (new File(path)).exists();
     if (exists)
     return true;     
     else
     return false;
     public static void main(String[] args)
          ApplicationTree app = new ApplicationTree();
}